Pharynx Anatomy (Parts, Layers, Muscles)

Overview

The pharynx is approximately 12–15 cm long and serves as a shared passageway for breathing and swallowing. It has three parts: the nasopharynx, oropharynx, and laryngopharynx.

Parts of the Pharynx and Swallowing

• Nasopharynx (pars nasalis): associated with the nasal cavity.
• Oropharynx (pars oralis): associated with the oral cavity.
• Laryngopharynx (pars laryngis): the lowest part, behind the larynx, continuing toward the esophagus.

During swallowing:

• The soft palate closes off the nasopharynx, helping keep food out of the nasal cavity.
• The epiglottis helps direct food away from the airway.
• The tongue pushes food backward and downward toward the esophagus.

Nasopharynx

The nasopharynx lies roughly at the level of C1–C2 and is attached to the base of the skull. Its upper attachment area is called the vault of the pharynx (fornix pharyngis). Attachment landmarks include:

• The pharyngeal tubercle of the occipital bone
• The petro-occipital fissure
• The inferior surface of the petrous part of the temporal bone
• The medial lamina of the pterygoid process

The choanae, or internal nasal openings, mark the boundary between the nasal cavity and the pharynx.

The auditory (Eustachian) tube connects the nasopharynx with the middle ear. It helps equalize pressure in the middle ear, particularly when it opens during swallowing, and drains the middle ear into the pharynx.

Key structures around the auditory tube include:

• Ostium pharyngeum tubae auditivae: the pharyngeal opening of the tube
• Torus tubarius: the raised cartilage around the opening
• Pharyngeal recess: the groove behind the torus tubarius
• Pharyngeal tonsil (adenoids) and tubal tonsils: nearby lymphoid tissue

Enlarged adenoids may obstruct the auditory tube.

Oropharynx

The oropharynx lies approximately at the level of C3–C4. It extends from the soft palate to the epiglottis and connects to the oral cavity through the isthmus faucium, or oropharyngeal isthmus.

Laryngopharynx

The laryngopharynx lies approximately at the level of C5–C6. It includes the laryngeal inlet and the opening toward the esophagus. A piriform fossa is present on each side.

Layers of the Pharyngeal Wall

The pharyngeal wall has four layers:

1. Tunica mucosa — lines the inside of the pharynx.
   • The nasopharynx is lined with respiratory-type epithelium: pseudostratified epithelium with cilia and goblet cells.
   • The rest of the pharynx has stratified squamous non-keratinized epithelium, which protects it from contact with food.
2. Tela submucosa — connective tissue containing blood vessels, lymph vessels, and glands.
3. Tunica muscularis — contains circular and longitudinal muscle fibers whose coordinated action supports pharyngeal peristalsis.
4. Tunica adventitia — an outer covering of tough collagen fibers.

Muscles of the Pharynx

The pharyngeal muscles are grouped into constrictors and elevators.

Pharyngeal Constrictors

The constrictors narrow the pharynx during swallowing and help move its contents downward.

• Superior pharyngeal constrictor
  • Origin: Pterygoid process, pterygomandibular raphe, and mylohyoid line of the mandible
  • Insertion: Pharyngeal raphe
• Middle pharyngeal constrictor (called “medial” in the subtitles)
  • Origin: Hyoid bone
  • Insertion: Pharyngeal raphe
• Inferior pharyngeal constrictor
  • Origin: Thyroid and cricoid cartilages
  • Insertion: Pharyngeal raphe

Pharyngeal Elevators

The elevators raise the pharynx during swallowing.

• Stylopharyngeus
  • Origin: Styloid process
  • Insertion: Lateral wall of the pharynx
• Palatopharyngeus
  • Origin: Aponeurosis of the soft palate
  • Insertion: Lateral wall of the pharynx
• Salpingopharyngeus
  • Origin: Wall of the auditory tube
  • Insertion: Fibers of the palatopharyngeus
  • Also associated with helping open the auditory tube during swallowing

Speaker and Sources

The video features a single narrator, who introduces himself as “Meditay.” The narration is accompanied by anatomical diagrams or a 3D anatomy model. No additional speakers or named external sources are identified.